Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/26—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies rotatable
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2411—Filter cartridges
  • B01D46/2414—End caps including additional functions or special forms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/0039—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices
  • B01D46/0041—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices for feeding
  • B01D46/0045—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices for feeding by using vanes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/0052—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with filtering elements moving during filtering operation
  • B01D46/0056—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with filtering elements moving during filtering operation with rotational movement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H3/00—Other air-treating devices
  • B60H3/06—Filtering
  • B60H3/0658—Filter elements specially adapted for their arrangement in vehicles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2275/00—Filter media structures for filters specially adapted for separating dispersed particles from gases or vapours
  • B01D2275/10—Multiple layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
  • B60H3/00—Other air-treating devices
  • B60H3/06—Filtering
  • B60H3/0658—Filter elements specially adapted for their arrangement in vehicles
  • B60H2003/0666—Filter elements specially adapted for their arrangement in vehicles the filter element having non-rectangular shape

Definitions

• the present invention relates to a filtration system releasably attachable to a blower wheel in an HVAC system, and in particular, to a filter cartridge having a plurality of compartments containing a filter medium and a plurality of substantially unimpeded air flow passages that maintain a high flow rate even when the filter medium is in a fully loaded state.
• HVAC heating, ventilation, and cooling systems
• the HVAC systems in most vehicles do not include air filters.
• Minimal space is generally available for retrofitting a filter to the HVAC system.
• space within the HVAC system is at a premium and it is difficult for some manufacturers to provide a location for an appropriate filter.
• U.S. Patent No. 5,265,348 discloses the use of a rotating foam material on a rotary fan to reduce noise.
• the present invention is directed to a filtration system attachable to a blower wheel in an HVAC system.
• the present filtration system is particularly useful to provide cabin air filtration to vehicles, which currently do not have a filter designed in the HVAC system. Movement of the filter cartridge with the blower wheel increases filtration efficiency during blower operation.
• the present moving filter cartridge can be retrofitted to most existing blower wheels.
• the filter cartridge releasably attaches to either the outside perimeter or the inside perimeter of the blower wheel.
• An advantage of the present filtration system is that it is retrofittable into most existing vehicles. Since most cars have a blower wheel, a space exists to place the present filter cartridge. On the other hand, it is not feasible to easily retrofit a vehicle with a conventional cabin air filter since little additional space is available. Locating the filter cartridge at the blower wheel provides filtration of both outside air entering the HVAC system and air being recirculated within the system. Most cabin air filters only filter the air as it enters the vehicle.
• the present filter cartridge includes both compartments containing a filter medium and flow passages of a size, density and shape such that a high flow rate is maintained even when the filter media is fully loaded.
• the spinning action of the filter cartridge causes the filter medium contained in the compartments to impact air as it passes through the flow passages.
• Some loss of filtration efficiency due the flow passages is offset by increased efficiency due to the movement of the filter cartridge with the blower wheel.
• the filtration system rotates in conjunction with a blower wheel.
• the blower wheel has a plurality of fan blades arranged in a spaced relationship radially around a blower cavity.
• the blower wheel defines a flow path extending radially outward from the blower cavity and through the fan blades when the blower wheel is rotating.
• the present filtration system can reduce the airflow through the blower wheel, thereby reducing the power consumption of the motor.
• the relationship between power and flow is a cubic function. By reducing the load (i.e., power consumption), the life of the
• the filter cartridge comprises a mesh structure forming a generally annular cylinder comprising a center opening, a plurality of compartments containing a filter medium, and spaces between the compartments.
• the spaces between the compartments comprise substantially unimpeded airflow passages that permit airflow even when the filter medium is fully loaded.
• the compartments may extend radially into the center opening.
• the compartments comprise one of corrugations or pleats in one or more of the mesh layers.
• the compartments can be shaped to operate as fan blades.
• the compartments are typically discrete pockets.
• the mesh typically comprises an expanded metal screen.
• a mesh material extends across a top opening of the annular cylinder.
• the filter medium can be selected from a group consisting of electret charged medium, particulate medium, sorbents medium, agglomerated carbon or combinations thereof.
• the filter cartridge comprises at least one end cap.
• An air flow passage can optionally extends through the at least one end cap.
• the end cap can also include weight balancing cavities and/or removable weight balancing tabs.
• the filter cartridge comprises a first mesh layer having a plurality of raised portions and a second mesh layer engaged with the first mesh layer such that the raised portions comprise compartments.
• a filter medium is retained in the compartments. Spaces between the compartments comprise substantially unimpeded airflow passages that permit airflow even when the filter medium is fully loaded.
• the filter medium is preferably agglomerated carbon or other filter medium such as activated carbon or other sorbents materials that remove odors and gases from the air, such as diesel exhaust, car exhaust, urban or farm smells, carbon monoxide, and ozone.
• Figure 1 is a perspective view of a filter cartridge in accordance with the present invention.
• Figure la is a sectional top view of the filter cartridge of Figure 1.
• Figure lb is a sectional top view of an alternate filter cartridge in accordance with the present invention.
• Figure 2a is a sectional view of the filter cartridge of Figure 1.
• Figure 2b is a sectional view of an alternate filter cartridge in accordance with the present invention.
• Figure 2c is a sectional view of another alternate filter cartridge in accordance with the present invention.
• Figure 3 is a perspective view of a filter cartridge engaged with a blower wheel in accordance with the present invention.
• Figure 4 is a sectional view of a filter cartridge engaged with a blower wheel in accordance with the present invention.
• Figure 5 is a sectional view of an alternate filter cartridge engaged with a blower wheel in accordance with the present invention.
• Figure 6 is a sectional view of another alternate filter cartridge engaged with a blower wheel in accordance with the present invention.
• Figure 6a is a sectional view of a filter cartridge engaged with an outer perimeter of a blower wheel in accordance with the present invention.
• Figure 7 is a top view of a filter cartridge engaged with a blower wheel in accordance with the present invention.
• Figure 8 is a graphic representation of data relating to gas removal efficiency of the present filter cartridges and a conventional filter cartridge.
• Figure 9 is a graphic representation of data relating to shaped blade inclination on airflow performance.
• Figure 10 is a graphic representation of data relating to shaped blade orientation on airflow performance.
• Figure 11 is a graphic representation of data relating to permeability of the filter cartridge cap on airflow performance.
• Figure 12 is a graphic representation of data relating to permeability of the filter cartridge cap on gas removal efficiency.
• Figure 13 is a graphic representation of data relating to permeability of the filter cartridge cap on airflow performance.
• the filter cartridge 20 includes a first mesh layer 22 defining an inner filter surface 24 and a second mesh layer 26 defining an outer filter surface 28.
• the first mesh layer 22 includes a plurality of raised portions 30 that protrude into center opening 32 of the filter cartridge 20. Gaps or spaces 34 located between the raised portions 30 on the first mesh layer 22 are abutted against the second mesh layer 26 so that the raised portions 30 define a plurality of compartments 40.
• the compartments 40 are preferably filled with a filter medium 42 (see e.g., Figure la).
• each of the compartments 40 define a discrete pocket that does not communicate with the adjacent compartments.
• the compartments 40 can be formed in a single mesh layer, obviating the second mesh layer.
• the gaps or spaces 34 between the compartments 40 comprise air flow passages 44 that allow for high initial air flow through the filter cartridge 20, that does not decrease over time. That is, the air flow passages 44 are substantially unimpeded when the filter medium 42 is fully loaded.
• the filter cartridge 20 includes a top cap 50 and a bottom cap 52. As best illustrated in Figure 2a, the caps 50, 52 serve to secure the first and second mesh layers 22, 26 together. The caps 50, 52 can also be used to retain the filter medium 42 in the filter cartridge 20.
• the caps 50, 52 can be constructed from a variety of materials, such as WO 01/60497 PCTVUSOO/18783
• the first and second mesh layers 22, 26 can be constructed from a variety of polymeric or metal screens or scrims. In the embodiment illustrated in Figure 1, the first and second mesh layers 22, 26 are constructed from expanded metal.
• the interface 33 between the gaps 34 on the first mesh layer 22 with the second mesh layer 26 may be held together by adhesives, spot welding or a variety of other techniques.
• the size or diameter of the openings in the mesh layers 22, 26 is preferably smaller than the smallest dimension of the particles.
• agglomerated carbon can be located in the compartments 40 and heat set to form a unitized sorbent mass. Consequently, the open area of the first and second mesh layers 22, 26 can be dramatically increased. Molded carbon particle agglomerate suitable for use in the present filter cartridge 20 are disclosed in U.S. Patent No. 5,332,426 (Tang et al.).
• Figure lb illustrates an alternate embodiment of the filter cartridge 20' having a web 35' that follows the contour of the first mesh layer 22'.
• the web 35' may be a particle filter or a scrim to assist in retaining the filter medium 42' in the compartments 40'.
• the web 35' may be useful to retain loose carbon in the compartments 40'. Preventing the filter medium 42' from escaping from the compartments 40' is important to prevent weight imbalances in the filter cartridge 22' from forming during usage.
• the web 35' is a particle filter located generally in the center of the compartments 40' and substantially surrounded by filter medium 42'
• the web 35' is located on the outer surface of mesh layer 22'.
• the filter cartridge 20' can be constructed using a variety of techniques.
• the web 35' can be bonded or laminated to the first mesh layer 22' either before or after formation of the raised portions 30'.
• the portion of the web 35' located along the gaps 34' is removed using mechanical or thermal processes. Consequently, the second mesh layer 26' is positioned directly against the first mesh layer 22' so that the flow passages 44' are substantially unimpeded by the web 35'.
• the portions of the web 35' along the gaps 34' are WO 01/60497 PCTVUSOO/18783
• the web 35' is sufficiently porous. That is, the web 35' can form a continuous layer around the filter 20'.
• FIG. 2b is a sectional view of an alternate filter cartridge 70 with a top cap 72 having one or more air flow passages 80, 81.
• Air flow passage 80 extends though the top mesh material 74 and outer mesh layer 84 of the filter cartridge 70.
• Air flow passage 81 extends through the inner mesh 77 and the outer mesh 84.
• the top cap 72 is constructed from an elastomeric material that secures outer mesh layer 84 to top mesh material 74.
• the top mesh material 74 includes a tab 75 that wraps around and is optionally attached to the inner mesh layer 77 to give the filter cartridge 70 additional structural integrity.
• Figure 2c is a sectional view of an alternate filter cartridge 70' with a top cap 72' having one or more air flow passages 80', 81', substantially as shown in Figure 2b.
• Air flow passage 80 extend though the top mesh material 74' and outer mesh layer 84' of the filter cartridge 70'.
• the top cap 72' secures outer mesh layer 84' to top mesh material 74'.
• the top mesh material 74' extends across the center opening 86 to prevent debris from collecting in the filter cartridge 70'.
• FIG 3 is an exploded view of a filter cartridge 100 in accordance with the present invention and schematic blower system 104.
• the filter cartridge includes an inner mesh layer 112 and an outer mesh layer 114, but no end caps.
• the filter medium (not shown) is retained in the compartments by friction, adhesives and/or a variety of other mechanisms.
• the filter medium can be retained in a pouch or bag constructed from a scrim or other porous material.
• the filter cartridge 100 can be located in blower cavity 106 so that the outer filter surface 108 forms a friction fit with fan blades 110 on the blower wheel 102.
• the filter cartridge 100 may be retained to the blower wheel 102 by a variety of active removable fastening techniques including mechanical fasteners, such as clips, hooks and hook and loop fasteners, and/or retaining tabs.
• the present filter cartridge 100 may be used as a conventional in-line filter for an HVAC system, such as disclosed in U.S. Patent No. 5,683,478 (Anonychuk).
• the filter cartridge 100 may be attached to a blower wheel 102 such as illustrated in Figure 3.
• Blower wheel 102 refers generically to any squirrel cage rotors, centrifugal rotors and the like. Clips or fasteners may be used to attached the filter cartridge 100 to the blower wheel 102, such as disclosed in commonly assigned U.S. Patent Serial No. 09/126,189, entitled Filtration System for HVAC Applications, filed June 30, 1998.
• the filter cartridge 100 preferably has a height generally equal to the height of the blower wheel 102.
• FIG. 4 is a sectional view of a filter cartridge 130 engaged with a blower wheel 132 in accordance with the present invention.
• the arrow 131 shows the direction of rotation of the assembly 130, 132.
• Shaped inner mesh layer 134 has a series of raised portions 136 separated by gaps 140.
• Outer mesh layer 138 is positioned against the inner mesh layer 134 to form radial compartments 144.
• Filter media 142 is deposited in the radial compartments 144 formed by the raised portions 136 abutted against the outer mesh layer 138.
• the number of compartments 144 can be greater than, less than or equal to the number of blades on the blower wheel 132.
• the gaps 140 form air flow passages 146 through the filter cartridge 130. Consequently, when the filter media 142 is fully loaded, the substantially unimpeded air flow passages 146 maintain adequate air flow through the filter cartridge 130.
• the filter cartridge 130 releasably attaches to either the outside perimeter or the inside perimeter of the blower wheel 132 (see Figures 6 and 6a).
• FIG. 5 is a sectional view of an alternate filter cartridge 160 engaged with a blower wheel 162 in accordance with the present invention.
• the arrow 161 shows the direction of rotation of the assembly 160, 162.
• the raised portions 164 formed in the inner mesh layer 166 are canted or inclined so that the compartments 165 act as a extensions of the fan blades 168.
• the raised portions 164 can be canted or inclined at an angle of inclination 167 of less than about 45 degrees relative to an axis 163 normal to the filter cartridge 160.
• a cant of ⁇ 4-5 degrees relative to axis 163 is also possible for some applications.
• the angle of inclination 167 is reversed (the filter cartridge 160 is flipped over).
• the shaping or inclination of the raised portions 164 increases the airflow though the filter cartridge 160 and blower wheel 162.
• the raised portions 164 are aligned and in-sync with the fan blades 168. As discussed in Example 4, locating the raised portions 164 out of sync with, or offset from, the fan blades 168 does not significantly diminish airflow.
• Figure 6 is a sectional view of an alternate filter cartridge 180 engaged with blower wheel 182 in accordance with the present invention.
• the embodiment of Figure 6 corresponds generally with Figure 4, except that the raised portions 184 are formed on the outer mesh layer 186.
• the inner mesh layer 188 that encloses raised portions 184 to form compartments 189 is cylindrical.
• the inner mesh layer 188 may include raised portions that may or may not be aligned with the raised portions 184 on the outer mesh layer 186.
• Figure 6a is a sectional view of an alternate filter cartridge 180' engaged with an outer perimeter of blower wheel 182' in accordance with the present invention. Raised portions 184' are formed on outer mesh layer 186'.
• Inner mesh layer 188' encloses raised portions 184' to form compartments 189' and engages with the outer perimeter of the blower wheel 182'.
• Figure 7 is a top view of a filter cartridge 190 engaged with a blower wheel
• Top cap 194 includes a series of removable weight balancing tabs 196 that can be trimmed or removed entirely to balance the blower wheel/filter cartridge assembly.
• top cap 194 may include a plurality of gaps 198 of known volume. By depositing a material of known density in the gaps 198, the same balancing procedure can be performed.
• the filter media is preferably a material having a useful level of resistance to penetration or transfer of particles and/or aerosols while retaining a desirable level of gas transport through the material. Resistance to permeation or transfer of particles and/or aerosols may be measured by determining the retention (filtration) of particles and can be expressed as clean air delivery rate (CADR), as defined in ANSI Standard AC-1 -1988.
• ACR clean air delivery rate
• the filter media may be paper, porous films of thermoplastic or hermoset materials, nonwoven webs of synthetic or natural fibers, scrims, woven or knitted materials, foams, or electret or electrostatically charged materials.
• the filter media may also include sorbents, catalysts, and/or activated carbon (granules, fibers, fabric, and molded shapes).
• Electret filter webs can be formed of the split fibrillated charged fibers as described in U.S. Pat. No. Re. 30,782. These charged fibers can be formed into a nonwoven web by conventional means and optionally joined to a supporting scrim such as disclosed in U.S. Pat. No. 5,230,800 forming an outer support layer.
• the support scrim can be a spunbond web, a netting, a Claf web, or the like.
• the nonwoven fibrous filter web can be a melt blown micro fiber nonwoven web, such as disclosed in
• Figure 8 shows a comparison of the gas removal efficiency of a conventional filter and two filter cartridges according to the present invention compared to a conventional cabin air filter.
• the conventional filter had about 82 grams of carbon.
• the blower filter with a diameter of about 12.95 centimeters (5.1-inches) had about 55 grams of carbon and the 11.4 centimeters (4.5-inches) diameter blower filter had about 20 grams of carbon.
• Each of the blower filters had the carbon generally equally divided among about 44 compartments (equal to the number of fan blades on the blower wheel). The compartments extended radially into the center opening of the blower wheel, as generally illustrated in Figure 4.
• the test was carried out by vaporizing toluene in a vaporization chamber and delivering the vaporized toluene in a carrier stream to a blower system without a filter cartridge.
• the amount of toluene required to deliver a concentration of 80 parts per million at a flow rate of about 200 cubic meters/hour (117 cubic feet/minute) through the blower wheel was determined.
• one of the filter cartridge described above was inserted into the blower wheel.
• Each of the filter cartridges was subjected to a toluene challenge of about 80 parts per million concentration with a flow rate of about 200 cubic meters/hour (117 cubic feet/minute). In this accelerated test about 15 minutes is roughly equal to one year of use in a car.
• the initial airflow reduction due to the blower filter is roughly equal to the 22% flow reduction of the conventional cabin air filter.
• the conventional filter airflow decreases with time, while the blower filter did not due to the non-plugging airflow passages. That is, the failure mode of the conventional air filter is a reduction in airflow, whereas the present blower filters maintain airflow even when the filter media is saturated.
• Example 3 Figure 10 illustrates the result of a test to determine the effect of the incline or cant direction of the shaped carbon blades on airflow.
• the angle of inclination of the shaped blades was about 25 degrees from an axis normal to the filter cartridge. Statistical bars showing the range of values are provided at the top of each bar.
• the same filter was used for both tests. The filter was placed in the blower wheel such that the carbon pockets inclined in a backward curved (BC) configuration. The same filter was then turned over such that the carbon pockets formed a forward curved (FC) configuration. The foiward curved configuration showed about an 18% improvement in airflow compared to the backward curved configuration (33% reduction vs. 27%). This test clearly shows the sensitivity of the airflow to the orientation of the carbon blades.
• a test to determine the sensitivity of the airflow to the alignment of the carbon blades with the blower wheel was carried out.
• the angle of inclination of the shaped blades was about 25 degrees from an axis normal to the filter cartridge.
• the carbon blades of the filter were aligned and in-sync with the blades of the blower wheel.
• the blades of the filter were offset about l/88 th of a revolution to the blower wheel blades.
• the aligned in-sync case improved the airflow by about 1%. This test established that it is not necessary to provide a feature to align the filter cartridge with the blower wheel blades.
• FIG 11 illustrates the respective airflow reduction using a perforated cap and a solid cap on the filter cartridge.
• the filter cartridge had a 11.4 centimeters (4.5-inches) diameter and contained about 20 grams of carbon.
• the angle of inclination of the shaped blades was about 25 degrees from an axis normal to the filter cartridge.
• Statistical bars showing the range of values are provided at the top of each bar.
• Example 6 is directed to evaluating the gas removal efficiency of the filter cartridges tested in Example 5. As illustrated in Figure 12, the gas removal efficiency of the perforated cap design was about 4-7% higher than that of the solid cap design.
• the gas test used toluene a concentration of about 80 parts per million and a flow rate of about 200 cubic meters/hour (1 17 cubic feet per minute) as described in Example 1. This test was carried out several times with the same result.
• Example 7 One possible explanation for the lower efficiency of the solid cap design is that the carbon located directly beneath the solid cap is not subject to much airflow. To determine if this was true, a test was conducted on a 11.4 centimeters (4.5-inches) diameter filter with 20 grams of carbon. The angle of inclination of the shaped blades was about 25 degrees from an axis normal to the filter cartridge. The same filter was used for tests with and without top caps. The filter was first tested without a top cap. A series of masking tape strips, about 2.54 millimeters (0.10 inches) in width were wrapped around the circumference of the filter beginning at the top. The open top filter showed a linear decrease in flow as progressive widths of tape masked the filter. The results are presented in Figure 13.

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• 2000
  • 2000-02-16 US US09/504,474 patent/US6348086B1/en not_active Expired - Fee Related
  • 2000-07-10 ES ES00947174T patent/ES2220494T3/es not_active Expired - Lifetime
  • 2000-07-10 AT AT00947174T patent/ATE268632T1/de not_active IP Right Cessation
  • 2000-07-10 KR KR1020027010525A patent/KR100760058B1/ko not_active IP Right Cessation
  • 2000-07-10 AU AU2000260829A patent/AU2000260829A1/en not_active Abandoned
  • 2000-07-10 CA CA002399430A patent/CA2399430A1/en not_active Abandoned
  • 2000-07-10 JP JP2001559586A patent/JP2003523820A/ja not_active Withdrawn
  • 2000-07-10 DE DE60011476T patent/DE60011476T2/de not_active Expired - Fee Related
  • 2000-07-10 WO PCT/US2000/018783 patent/WO2001060497A1/en active IP Right Grant
  • 2000-07-10 EP EP00947174A patent/EP1257342B1/en not_active Expired - Lifetime
• 2001
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